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Earlobe

February 15, 2024

The human earlobe (lobulus auriculae), the lower portion of the outer ear, is composed of tough areolar and adipose connective tissues, lacking the firmness and elasticity of the rest of the auricle (the external structure of the ear). In some cases the lower lobe is connected to the side of the face. Since the earlobe does not contain cartilage[1] it has a large blood supply and may help to warm the ears and maintain balance. However, earlobes are not generally considered to have any major biological function.[2] The earlobe contains many nerve endings, and for some people is an erogenous zone.

Earlobe
Details
SystemAuditory system
Identifiers
Latinlobulus auriculae (singular), lobuli auricularum (plural)
TA98A15.3.01.003
TA2105
FMA60984
Anatomical terminology
[edit on Wikidata]

The zoologist Desmond Morris in his book The Naked Ape (1967) conjectured that the lobes developed as an additional erogenous zone to facilitate the extended sexuality necessary in the evolution of human monogamous pair bonding.[3]

A free earlobe
An attached earlobe

Organogenesis edit

The earlobe, as a body part built of epithelium and connective tissue, might appear to be derived from dermatome.[4] But this is not the case, as in the surrounding tissue there are no somites and thus no dermatome. In this area, the dermis is derived from cells of mesenchymal cells: the mesenchyme is derived from the sclerotome and splanchnopleura located in the nearby regions of the torso.[5]

The earlobe as a body part arises and develops in the vicinity of auricular follicle, as a result of cascade induction:[6]

  1. The first-level inductor is the central segment of Archenteron's roof, which induces the production of the Medulla oblongata (part of the Hindbrain).
  2. The second-level inductor is the Medulla oblongata, which induces the production of a pair of auricular follicles derived from the mesoderm.
  3. The third-level inductor is the auricular follicle, which induces the production of the auditory bulla.

Genetics edit

 
Clint Eastwood, who has an extreme form of attached ear lobe.

Earlobes average about 2 centimeters long, and elongate slightly with age.[7] Although the "free" vs. "attached" appearance of earlobes is often presented as an example of a simple "one gene – two alleles" Mendelian trait in humans, earlobes do not all fall neatly into either category; there is a continuous range from one extreme to the other, suggesting the influence of several genes.[8][9][10]

Recessive gene frequency in the selected worldwide populations
Population N Recessive gene frequency
(for attached ear lobes) 		Source
Africans ? 0.60 Messeri (1976)[11]
Afroamericans 242 0.56 Glass et al. (1952)[12]
Ainu ? 0.49 Messeri (1967)[11]
Babinga ? 0.87 Messeri (1967)[11]
Bavaria ? 0.84 Messeri (1967)[11]
Bosnia and Herzegovina 7,325 0.55 Hadžiselimović (1981)[13]
Brazil ? 0.34 Saldanha (1960)[14]
Cameroon ? 0.83 Messeri (1967)[11]
Canadian Aboriginals 532 0.68 Chaison (1963)[15]
China ? 0.62 Messeri (1967)[11]
Hong Kong 70 0.80 Lai, Walsh (1966)[16]
India: Bengal 100 0.49 Dutta (1963)[17]
Japan 70 0.82 Lai, Walsh (1966)[16]
Laponia ? 0.71 Messeri (1967)[11]
Micronesia ? 0.52 Messeri (1967)[11]
Nepal 169 0.66 Bhasin (1969)[18]
New Guinea 399 0.80 Lai, Walsh (1966)[16]
Nicobar 813 0.81 Gabel (1958)[19]
Papuans ? 0.54 Messeri (1967)[11]
Polynesia ? 0.39 Messeri (1967)[11]
Russia ? 0.59 Messeri (1967)[11]
Sardinia 403 0.53 Messeri (1967)[11]
Scotland 500 0.48 Chattopadhyay (1968)[20]
Somalia ? 0.42 Messeri (1967)[11]
Sweden 247 0.59 Wiener (1937)[21]
Tibet ? 0.68 Tiwari, Bhasin (1969)[22]
United States: Baltimore 380 0.63 Glass et al. (1952)[12]
United States: Brooklyn 248 0.92 Wiener (1937)[21]
United States: Buffalo 381 0.43 Dronamraju (1966)[23]
United States: Pennsylvania 241 0.50 Glass et al. (1952)[12]

Clinical issues edit

Earlobes are normally smooth, but occasionally exhibit creases. Creased earlobes are sometimes associated with genetic disorders in children, including Beckwith-Wiedemann syndrome.[24] In some early studies, earlobe creases were thought to be associated with an increased risk of heart attack and coronary heart disease. But more recent studies have concluded that, since earlobes become more creased with age, and older people are more likely to have heart disease than younger people, age rather than intrinsic factors may account for the findings linking heart attack to earlobe creases.[24] The earlobe crease is also called Frank's Sign.

Society and culture edit

 
Stretched earlobe piercing, Ethiopia

Earlobe piercing and stretching edit

Piercing the earlobes is a commonplace activity in many cultures in many historical eras; no other location on the body is as commonly pierced. Consequently, injury to the earlobe due to the weight of heavy earrings is also common.[25] Some cultures practice earlobe stretching for decorative effects, using piercing ornaments to stretch and enlarge the earlobes to accommodate plugs.

Negative effects of wearing earrings edit

Some research has found that the most frequent complications connected with wearing earrings are:[26]

A noticeable relationship has been found by Polish scientists between the piercing of young girls' earlobes and their subsequently developing allergic skin reactions.[27][28][29] In the view of Professor Ewa Czarnobilska, the manager of the research team, the primary reason for the allergies connected to earrings is the presence of nickel, which is a common component of the alloys used in jewelry production and leaches from the earrings.[28][29] The symptom seen is generally eczema, and is often misdiagnosed as a food allergy, for instance to milk. The specific mechanism in allergies caused by earrings is the contact of nickel ions with the lymphatic system.[28][29]

The study noted that children who stopped wearing earrings did not see the disappearance of the allergic symptoms. The immune system remembers the presence of the nickel ions in the person's blood and lymph, so the child can still react to:[28][29]

  • metal parts of wardrobe,
  • dental braces,
  • dental prosthesis,
  • orthotics,
  • meals cooked in pots with addition of nickel,
  • margarine (nickel is a catalyst in hydrogenation of unsaturated fats),
  • coins,
  • chocolate,
  • nuts,
  • leguminous vegetables,
  • wine, and
  • beer.

Research by allergists has found that in a sample of 428 pupils of ages 7–8 and 16–17 years old:[28][29]

  • 30% of the research population showed an allergy to nickel, and
  • the allergy occurred in girls who had started wearing earrings in early childhood.

References edit

  1. ^ Steinberg, Avraham (2003). Encyclopedia of Jewish Medical Ethics: a Compilation of Jewish Medical Law on All Topics of Medical Interest. Jerusalem: Feldheim Publishers. p. 350. ISBN 1583305920.
  2. ^ Popelka (31 August 1999). "Re:Why do we have earlobes, what are they for, since when?". MadSci Network. Retrieved 16 July 2015.
  3. ^ Desmond Morris The Naked Ape: A Zoologist's Study of the Human Animal (Hardback: ISBN 0-07-043174-4; Reprint: ISBN 0-385-33430-3) Jonathan Cape, 1967 . Chapter 2, page 59 of Corgi paperback ed
  4. ^ Jura, Krzanowska & Rzehak 1983, p. 355, 357.
  5. ^ Jura, Krzanowska & Rzehak 1983, p. 358.
  6. ^ Jura, Krzanowska & Rzehak 1983, p. 395.
  7. ^ Azaria R, Adler N, Silfen R, Regev D, Hauben DJ (June 2003). "Morphometry of the adult human earlobe: a study of 547 subjects and clinical application". Plast. Reconstr. Surg. 111 (7): 2398–2402, discussion 2403–2404. doi:10.1097/01.PRS.0000060995.99380.DE. PMID 12794488. S2CID 38636234.
  8. ^ Mader S. S. (2000): Human Biology. McGraw–Hill, New York, ISBN 0-07-290584-0.
  9. ^ Boaz N. T. (1999): Essentials of biological anthropology. Prentice Hall, New Jersey,ISBN 0-13-080793-1.
  10. ^ Dutta, P; Ganguly, P (1965). "Further Observations on Ear Lobe Attachment". Acta Genet Stat Med. 15: 77–86. doi:10.1159/000151894. PMID 14277139.
  11. ^ a b c d e f g h i j k l m Messeri E. (1967): "Variabilità morfologica del lobolo auricolare in Sardegna". Atti Soc. Peloritana, Sc. Fis. mat. nat., 13 (1/2): 89.
  12. ^ a b c Glass B., Sacks M. S., John E. F., Hess C. (1952): "Genetic Drift in a Religious Isolate: An Analysis of the Causes of Variation in Blood Group and Other Gene Frequencies in a Small Population". Phys. Anthrop., 144.
  13. ^ Hadžiselimović R. (1981): "Genetic distance among local human populations in Bosnia and Herzegovina (Yugoslavia)". Coll. Antrop., 5. (Suppl.): 63–66.
  14. ^ Saldanha, P. H. (1960). "Frequencies of consanguineous marriages in North-east of São Paulo, Brazil". Acta Genet. 10 (1): 71–88. doi:10.1159/000151120. PMID 13745577.
  15. ^ Chaisson, L. P. (1963). "Gene frequencies in the Micmac Indians". J. Hered. 54 (2): 229–36. doi:10.1093/oxfordjournals.jhered.a107255. PMID 14086177.
  16. ^ a b c Lai, Y. C.; Walsh, R. J. (1966). "Observation on ear lobe types". Acta Genet. Statist. Med. 16 (3): 250–7. doi:10.1159/000151971. PMID 5953713.
  17. ^ Dutta, P. C. (1963). "A note on the ear lobe". Acta Genet. Statist. Med. 15 (3): 290–4. doi:10.1159/000151809. PMID 14101393.
  18. ^ Bhasin, M. K. (1969). "Ear lobe attachment among Newars of Nepal". Hum. Hered. 19 (5): 506–8. doi:10.1159/000152259. PMID 5365889.
  19. ^ Gabel, N. E. (1958). "A racial study of the Fijans". Anthrop. Rec. 20 (1): 22.
  20. ^ Chatopadhyay, P. K. (1968). "A note on the ear lobe attachment among the Jats and Ahirs". Acta Genet. Statist. Med. 18 (3): 277–82. doi:10.1159/000152145. PMID 5694908.
  21. ^ a b Wiener (1937). "Complications in ear genetics". J. Hered. 28 (3): 425. doi:10.1093/oxfordjournals.jhered.a104304.
  22. ^ Tiwari, S. C.; Bhasin, M. K. (1969). "Frequency of hand clasping and ear lobe attachment in Tibetians". J. Hered. 19 (4): 658–661. doi:10.1159/000152280. PMID 5399262.
  23. ^ Dronamraju, K. R. (1966). "Ear lobe attachment in the Buffalo region". Acta Genet. Statist. Med. 16 (3): 258–64. doi:10.1159/000151972. PMID 5953714.
  24. ^ a b MedlinePlus Encyclopedia: Earlobe creases
  25. ^ HELGAADMIN (15 December 2014). "Are your Earlobes Attached?". Quantum Healing Institute Blog.
  26. ^ Watson, D (2002). "Torn earlobe repair". Otolaryngologic Clinics of North America. 35 (1): 187–205, vii–viii. doi:10.1016/s0030-6665(03)00102-6. PMID 11781215.
  27. ^ Harmful earrings (pl. Szkodliwe kolczyki), Fizjointormator. Retrieved 2015-04-01
  28. ^ a b c d e Polish Scientists learn: earrings harm children (pl. Polscy naukowcy ostrzegają: kolczyki szkodzą dzieciom) Tvn24. Retrieved 2015-04-01
  29. ^ a b c d e Czarnobilska E.; Oblutowicz K.; Dyga W.; Wsołek-Wnek K.; Śpiewak R. (May 2009). "Contact hypersensitivity and allergic contact dermatitis among school children and teenagers with eczema". Contact Dermatitis. John Wiley & Sons A/S. 60 (5): 264–269. doi:10.1111/j.1600-0536.2009.01537.x. PMID 19397618. S2CID 30920753.

Further reading edit

February 15, 2024
earlobe, human, earlobe, lobulus, auriculae, lower, portion, outer, composed, tough, areolar, adipose, connective, tissues, lacking, firmness, elasticity, rest, auricle, external, structure, some, cases, lower, lobe, connected, side, face, since, earlobe, does. The human earlobe lobulus auriculae the lower portion of the outer ear is composed of tough areolar and adipose connective tissues lacking the firmness and elasticity of the rest of the auricle the external structure of the ear In some cases the lower lobe is connected to the side of the face Since the earlobe does not contain cartilage 1 it has a large blood supply and may help to warm the ears and maintain balance However earlobes are not generally considered to have any major biological function 2 The earlobe contains many nerve endings and for some people is an erogenous zone EarlobeDetailsSystemAuditory systemIdentifiersLatinlobulus auriculae singular lobuli auricularum plural TA98A15 3 01 003TA2105FMA60984Anatomical terminology edit on Wikidata The zoologist Desmond Morris in his book The Naked Ape 1967 conjectured that the lobes developed as an additional erogenous zone to facilitate the extended sexuality necessary in the evolution of human monogamous pair bonding 3 A free earlobeAn attached earlobe Contents 1 Organogenesis 2 Genetics 3 Clinical issues 4 Society and culture 4 1 Earlobe piercing and stretching 4 2 Negative effects of wearing earrings 5 References 6 Further readingOrganogenesis editThe earlobe as a body part built of epithelium and connective tissue might appear to be derived from dermatome 4 But this is not the case as in the surrounding tissue there are no somites and thus no dermatome In this area the dermis is derived from cells of mesenchymal cells the mesenchyme is derived from the sclerotome and splanchnopleura located in the nearby regions of the torso 5 The earlobe as a body part arises and develops in the vicinity of auricular follicle as a result of cascade induction 6 The first level inductor is the central segment of Archenteron s roof which induces the production of the Medulla oblongata part of the Hindbrain The second level inductor is the Medulla oblongata which induces the production of a pair of auricular follicles derived from the mesoderm The third level inductor is the auricular follicle which induces the production of the auditory bulla Genetics edit nbsp Clint Eastwood who has an extreme form of attached ear lobe Earlobes average about 2 centimeters long and elongate slightly with age 7 Although the free vs attached appearance of earlobes is often presented as an example of a simple one gene two alleles Mendelian trait in humans earlobes do not all fall neatly into either category there is a continuous range from one extreme to the other suggesting the influence of several genes 8 9 10 Recessive gene frequency in the selected worldwide populations Population N Recessive gene frequency for attached ear lobes SourceAfricans 0 60 Messeri 1976 11 Afroamericans 242 0 56 Glass et al 1952 12 Ainu 0 49 Messeri 1967 11 Babinga 0 87 Messeri 1967 11 Bavaria 0 84 Messeri 1967 11 Bosnia and Herzegovina 7 325 0 55 Hadziselimovic 1981 13 Brazil 0 34 Saldanha 1960 14 Cameroon 0 83 Messeri 1967 11 Canadian Aboriginals 532 0 68 Chaison 1963 15 China 0 62 Messeri 1967 11 Hong Kong 70 0 80 Lai Walsh 1966 16 India Bengal 100 0 49 Dutta 1963 17 Japan 70 0 82 Lai Walsh 1966 16 Laponia 0 71 Messeri 1967 11 Micronesia 0 52 Messeri 1967 11 Nepal 169 0 66 Bhasin 1969 18 New Guinea 399 0 80 Lai Walsh 1966 16 Nicobar 813 0 81 Gabel 1958 19 Papuans 0 54 Messeri 1967 11 Polynesia 0 39 Messeri 1967 11 Russia 0 59 Messeri 1967 11 Sardinia 403 0 53 Messeri 1967 11 Scotland 500 0 48 Chattopadhyay 1968 20 Somalia 0 42 Messeri 1967 11 Sweden 247 0 59 Wiener 1937 21 Tibet 0 68 Tiwari Bhasin 1969 22 United States Baltimore 380 0 63 Glass et al 1952 12 United States Brooklyn 248 0 92 Wiener 1937 21 United States Buffalo 381 0 43 Dronamraju 1966 23 United States Pennsylvania 241 0 50 Glass et al 1952 12 Clinical issues editEarlobes are normally smooth but occasionally exhibit creases Creased earlobes are sometimes associated with genetic disorders in children including Beckwith Wiedemann syndrome 24 In some early studies earlobe creases were thought to be associated with an increased risk of heart attack and coronary heart disease But more recent studies have concluded that since earlobes become more creased with age and older people are more likely to have heart disease than younger people age rather than intrinsic factors may account for the findings linking heart attack to earlobe creases 24 The earlobe crease is also called Frank s Sign Society and culture edit nbsp Stretched earlobe piercing EthiopiaEarlobe piercing and stretching edit Piercing the earlobes is a commonplace activity in many cultures in many historical eras no other location on the body is as commonly pierced Consequently injury to the earlobe due to the weight of heavy earrings is also common 25 Some cultures practice earlobe stretching for decorative effects using piercing ornaments to stretch and enlarge the earlobes to accommodate plugs Negative effects of wearing earrings edit Some research has found that the most frequent complications connected with wearing earrings are 26 inflammation keloids loss of tissue by tearing and mechanical division of earlobes A noticeable relationship has been found by Polish scientists between the piercing of young girls earlobes and their subsequently developing allergic skin reactions 27 28 29 In the view of Professor Ewa Czarnobilska the manager of the research team the primary reason for the allergies connected to earrings is the presence of nickel which is a common component of the alloys used in jewelry production and leaches from the earrings 28 29 The symptom seen is generally eczema and is often misdiagnosed as a food allergy for instance to milk The specific mechanism in allergies caused by earrings is the contact of nickel ions with the lymphatic system 28 29 The study noted that children who stopped wearing earrings did not see the disappearance of the allergic symptoms The immune system remembers the presence of the nickel ions in the person s blood and lymph so the child can still react to 28 29 metal parts of wardrobe dental braces dental prosthesis orthotics meals cooked in pots with addition of nickel margarine nickel is a catalyst in hydrogenation of unsaturated fats coins chocolate nuts leguminous vegetables wine and beer Research by allergists has found that in a sample of 428 pupils of ages 7 8 and 16 17 years old 28 29 30 of the research population showed an allergy to nickel and the allergy occurred in girls who had started wearing earrings in early childhood References edit Steinberg Avraham 2003 Encyclopedia of Jewish Medical Ethics a Compilation of Jewish Medical Law on All Topics of Medical Interest Jerusalem Feldheim Publishers p 350 ISBN 1583305920 Popelka 31 August 1999 Re Why do we have earlobes what are they for since when MadSci Network Retrieved 16 July 2015 Desmond Morris The Naked Ape A Zoologist s Study of the Human Animal Hardback ISBN 0 07 043174 4 Reprint ISBN 0 385 33430 3 Jonathan Cape 1967 Chapter 2 page 59 of Corgi paperback ed Jura Krzanowska amp Rzehak 1983 p 355 357 Jura Krzanowska amp Rzehak 1983 p 358 Jura Krzanowska amp Rzehak 1983 p 395 Azaria R Adler N Silfen R Regev D Hauben DJ June 2003 Morphometry of the adult human earlobe a study of 547 subjects and clinical application Plast Reconstr Surg 111 7 2398 2402 discussion 2403 2404 doi 10 1097 01 PRS 0000060995 99380 DE PMID 12794488 S2CID 38636234 Mader S S 2000 Human Biology McGraw Hill New York ISBN 0 07 290584 0 Boaz N T 1999 Essentials of biological anthropology Prentice Hall New Jersey ISBN 0 13 080793 1 Dutta P Ganguly P 1965 Further Observations on Ear Lobe Attachment Acta Genet Stat Med 15 77 86 doi 10 1159 000151894 PMID 14277139 a b c d e f g h i j k l m Messeri E 1967 Variabilita morfologica del lobolo auricolare in Sardegna Atti Soc Peloritana Sc Fis mat nat 13 1 2 89 a b c Glass B Sacks M S John E F Hess C 1952 Genetic Drift in a Religious Isolate An Analysis of the Causes of Variation in Blood Group and Other Gene Frequencies in a Small Population Phys Anthrop 144 Hadziselimovic R 1981 Genetic distance among local human populations in Bosnia and Herzegovina Yugoslavia Coll Antrop 5 Suppl 63 66 Saldanha P H 1960 Frequencies of consanguineous marriages in North east of Sao Paulo Brazil Acta Genet 10 1 71 88 doi 10 1159 000151120 PMID 13745577 Chaisson L P 1963 Gene frequencies in the Micmac Indians J Hered 54 2 229 36 doi 10 1093 oxfordjournals jhered a107255 PMID 14086177 a b c Lai Y C Walsh R J 1966 Observation on ear lobe types Acta Genet Statist Med 16 3 250 7 doi 10 1159 000151971 PMID 5953713 Dutta P C 1963 A note on the ear lobe Acta Genet Statist Med 15 3 290 4 doi 10 1159 000151809 PMID 14101393 Bhasin M K 1969 Ear lobe attachment among Newars of Nepal Hum Hered 19 5 506 8 doi 10 1159 000152259 PMID 5365889 Gabel N E 1958 A racial study of the Fijans Anthrop Rec 20 1 22 Chatopadhyay P K 1968 A note on the ear lobe attachment among the Jats and Ahirs Acta Genet Statist Med 18 3 277 82 doi 10 1159 000152145 PMID 5694908 a b Wiener 1937 Complications in ear genetics J Hered 28 3 425 doi 10 1093 oxfordjournals jhered a104304 Tiwari S C Bhasin M K 1969 Frequency of hand clasping and ear lobe attachment in Tibetians J Hered 19 4 658 661 doi 10 1159 000152280 PMID 5399262 Dronamraju K R 1966 Ear lobe attachment in the Buffalo region Acta Genet Statist Med 16 3 258 64 doi 10 1159 000151972 PMID 5953714 a b MedlinePlus Encyclopedia Earlobe creases HELGAADMIN 15 December 2014 Are your Earlobes Attached Quantum Healing Institute Blog Watson D 2002 Torn earlobe repair Otolaryngologic Clinics of North America 35 1 187 205 vii viii doi 10 1016 s0030 6665 03 00102 6 PMID 11781215 Harmful earrings pl Szkodliwe kolczyki Fizjointormator Retrieved 2015 04 01 a b c d e Polish Scientists learn earrings harm children pl Polscy naukowcy ostrzegaja kolczyki szkodza dzieciom Tvn24 Retrieved 2015 04 01 a b c d e Czarnobilska E Oblutowicz K Dyga W Wsolek Wnek K Spiewak R May 2009 Contact hypersensitivity and allergic contact dermatitis among school children and teenagers with eczema Contact Dermatitis John Wiley amp Sons A S 60 5 264 269 doi 10 1111 j 1600 0536 2009 01537 x PMID 19397618 S2CID 30920753 Further reading editJura Czeslaw Krzanowska Halina Rzehak Karol 1983 Podstawy embriologii zwierzat Bases of Animals Embryology 1st ed Warsaw Wydawnictwo Naukowe PWN En Polish Scientific Publishers PWN ISBN 83 01 04241 9 Retrieved from https en wikipedia org w index php title Earlobe amp oldid 1200669594, wikipedia, wiki, book, books, library,

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